1. Field of the Invention
The invention relates to communication devices and more particularly to such a device for the conversion of scraps of plastics, especially of thermoplastic foils and blow mold particles, into a free-flowing granulated material.
2. Description of the Prior Art
A knife and driving shaft assembly is arranged in a housing and cooperates with a counterknife assembly whereby the goods to be comminuted can be fed to the knife and driving shaft assembly with the present invention relating to a suitable and advantageous design of such a comminution device. Crushers of the type designed for the comminution of scraps of plastics are already known. In the prior forms of structure two or more cutter-beams are provided which are connected to a rotating shaft, with the cutter beams cooperating with a stationary knife. The foil to be chopped up is first cut into strips and these strips have to be repeatedly fed again to the knives or cutters in order to obtain a free-flowing mass. Moreover, screens are provided for the cutting-crushers which prevent the granular material emerging from the crusher before a certain grain size is obtained.
In the prior art the scraps to be comminuted had to be repeatedly rotated around with the knife and driving shaft assembly which meant that not only was the cost of the prior art crusher considerable, but that above all, the collected scraps were not processed in a continuous manner. Rather, breakdowns of the operations occurred through cloggings or through an insufficient processing capacity. Moreover, siren-like noises were created due to the knives or cutters rotating at high rotational speeds and this interfered with the operating personnel.
Based on the high noise level of between 90 and 105 decibles depending on the type of construction of the crusher, the use of thickwalled cast elements and antidroning devices it has not as yet been feasible to use cutting crushers as supplementary devices to a processing machine since the noises of the crushers can be heard above the noises of the processing machine, so that the acoustical control of the latter was not possible. Furthermore, thin foils, such as for example adhesive tapes, cannot be comminuted with hitherto known crusher structures since the cutting gap between the rotating and the stationary curring-beans cannot be adjusted to a dimension equalling approximately half of the foil thickness.